1. Field of the Invention
This invention relates generally to newly isolated proteins and more particularly to proteins either isolated in purified form from the human spleen or chemically synthesized, and to therapeutic compositions and methods for employing the same.
2. Description of the Prior Art
Immunomodulatory proteins have been isolated from bovine spleen and thymus, and have been analyzed to determine their respective amino acid residue sequences. Additionally, small peptides have been chemically synthesized which mimic the biological activity of the isolated naturally occurring, proteins and have been further modified to be provided with additional attributes such as resistence to enzymic action. A large body of articles and patents have now been published relating to such proteins and synthesized peptides. In particular, see for example Goldstein, G. (1974) Nature (London) 247, 11-14; Basch, R. S. and Goldstein, G. (1974) Proc. Natl. Acad. Sci. U.S.A. 71, 1474-1478; Scheid, M. P., Goldstein, G. and Boyse, E. A. (1978) J. Exp. Med. 147, 1727-1743; Scheid, M. P., Goldstein, G. and Boyse, E. A. (1975) Science 190, 1211-1213; Ranjes, G. E. Scheid, M. P., Goldstein, G. and Boyse, E. A. (1982) J. Exp. Med. 156, 1057-1064; Vankatasubramanian, K., Andhya, T. and Goldstein, G. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 3171-3174; Malaise M. G., Harz-Hazelstein, M. T., Reuter, A. M., Vrinds-Geort, Y., Goldstein G., and Franchmint, P. (1986) in Immunoregulatory UCLA Symposium on Molecular and Celular Biology, eds. Goldstein, G., Wigzell, H. and Bach, J. F. (Liss, New York),; Sunshine, G. H., Basch, R. S., Coffey, R. G., Cohen, K. W., Goldstein, G. and Hadden, J. W. (1978) J. Immunol. 120, 1594-1599. See also U.S. Pat. Nos. 4,190,646; 4,261,886; 4,361,673; 4,420,424; 4,629,723 and 4,505,853.
The hormone splenin (SP) as obtained from bovine spleen has been described in Audhya et al. Biochemistry, 20, 6195-6200 (1981). As described therein, bovine splenin (bSP) has been determined to be a 49 amino acid residue peptide having an amino acid residue sequence differing from bovine thymopoietin (bTP) by two amino acid residues at positions 34 and 43. This difference is significant in that the 34 position is believed to lie within the active-site region of the protein and a change therein will affect the receptor specifications and biological activity of the molecule.
While extensive work has been done in connection with bovine SP, to date however, human SP (hSP) has not been isolated from human spleen tissue and, of course, neither has the protein been completely sequenced or synthesized.